Vulcanizing mold for rubber footwear



Dec. 29 1925 D. F. WlLHELMl VULCANIZING MOLD FOR RUBBER FOOTWEAR Filed August 13, 1924 wwuu.

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Patented Dec. 29, 1925.

UNITED STATES 1,567,479 PATENT OFFICE.

DIRK IRAN$ WILHELMI, F DOOIRMTERTH, NEAR ARNHEM, NETHERLANDS, AS-

' 3IGNORTO VEREENIGDE NEDERLANDSCHE RUBBEBFABRIEKEN, OF HEVEADORP,

NETHERLANDS, A DUTCH COMPANY VULCANIZING MOLD FOR RUBBER FOOTWEAR.

Application filed August 13, 1924. Serial No. 731,860.

T 0 all tuba-m. it may concern Be it known that I, DIRK FRANS Win- HELMI, a sub ect of the Queen of the Neth erlands, residing at Doorwerth, near Arnfi hem, Netherlands, have invented certain last or shoe-support 6, the preferred posiuseful improvements in the manufacture of of the upper-mold 7, which is provided with new and useful Improvements in Vulcanizing Molds for Rubber Footwear, of which the following is a specification.

This invention relates to certain novel and rubber footwear such as, for instance, sandals,'blucher shoes, etc., and has particular application to improvements in'the construction and arrangement of the vulcanizing mold parts.

In my previous process of manufacturing molded rubber footwear a four-part mold is employed, said mold being composed of two side molds, a sole-mold and a last or form and Fig. 4 is a vertical longitudinal sectional view ofan auxiliary last.

Referring now to the drawing in detail,

5 designate-s a last post or stem carrying the tion of which being as shown with the sole portion uppermost. The lower end 5 of the post or stem 5 is tapered so as to make a snug fit ina correspondingly shaped seat '7 a matrice adapted to receive not only the front portionor vamp of the shoe, but also the sides and the back thereof up to the plane 8 where the upper joins the sole. The third section of the mold is the top or solemold 9, the matrice of which has a contour adapted to mold the balance, i. e. the sole 11 and the heel 12 on the shoe.

It will be readily understood that it is for supporting the shoe to be molded. necessary for the molds 7 and 9 to be so a seam, rib or fin of rubber which extends from the opening at the top of the shoe down where the upper joins the toe. This is to some extent disadvantageous 'as it mars the appearance of the shoe and also for the reason that where the side molds join onthe center line they are liable to pinch or crimp the lining of the shoe in between the two parts, whereby the article is damaged.

In order to avoid the said disadvantage I have suggested to employ a five-part mold comprisi.1g a front member adapted to act as a mold for a portion of the instep, two side members for receiving that portion of the shoe between the front mold members and the heel, a sole-mold and a last or worksupport, but such a five-part mold, while avoiding a seam over the vamp, has the inconvenience that it is still more diflicult to I make with the required accuracy in view of the high pressure which it has to stand during the vulcanization.

IL-II in Fig. 1, Fig. 3 is a cross-sectional view taken along the line III-III in Fig. 1

formed that the walls of their matrices, starting from the plane of junction 8, are more or less inwardly inclined, as any outward slope of these walls would interfere 25 across the instep and to the end of the toe with the proper removal of said molds after the vulcanization and tend to damage the article. This inward slope of the walls all around the matrices is a characteristic feature of my novel mold and one which, as far as I am aware, is not met in any other mold for rubber shoes. -Figs. 1, 2 and 3 of the drawing are illustrative of this special form of the molds, but obviously any cross or longitudinal section over'the mold would bring out the said novel feature.

The upper face of mold 7 and the lower face of mold 9 are formed with rims or bosses a and]; surrounding the edges of the mold cavities and meeting in sharp edges on the interior of the mold. These shear r a cross-sectional view taken along the line pins 14' tted to corresponding sockets 15in the sole-mold 9. a

The means for operating the molds 7 and 9 to force them up against the shoe made up on the last or work support 6 have not been shown as they do not form part of my present invention, but I wish it to be understood thatthe required pressure may be brought about by any conventional orconvenient instrumentalities for this purpose. Neither does the drawing illustrate the means for simultaneously raising the temperatureof the shoe as any one skilled in the art will know how to bring about the required heat. K After the vulcanization or cure the mold sections 7 and9 are moved away from each other and the shoe taken off the last 6. In

view of the fact that the contours of the last.

6 correspond with those of the matrices in themolds it goes without saying that during this removal of the last the shoe must be put under tensional stress, so that it is essential for the lining of the shoe to be sufiiciently elastic. In practice I have found that with a lining of knitted web or texture very satisfactory results are obtained, but instead of knitted fabric, canvas, duck or other woven material may be used, provided thethreads thereof run more or less diagonally.

' heel Bend the ball portion. Such a metallic shank is of essential importance in shoes provided with heels for supporting the cipal feature of the invention is to avoid the ,necessity of using more than two mold sections in addition to the last or form.

Having thus described my invention, what I claim as new, and desire to secure by Let: ters Patent, is

1. A method of manufacturing rubber footwear which consists in first vulcanizing the article under pressure. in a mold comrising an upper-mold, a sole-mold and a ast for supporting the article, and thereafter subjecting the article to anafter-cure on another last.

2. A method of manufacturing rubber footwear which consists in first vul'canizing the article under pressure in a mold comprising an upper-mold, a sole-mold and a last for supporting the article, the ,matrices of the mold sections being so formed that their walls, startingfrom the plane of junc tion of said sections, slope more or less inwardly, and thereafter subjecting the article to an after-cure on a last presenting the de-. sired final form.

3. A method of -manufacturing rubber footwear which. consists of first vulcanizing the article under pressure in a mold comprising a section to receive the entire upper, a sole section and a last for supporting the article, and thereafter subjecting the article to an aftercure on another last.

In. testimony whereof I aflix my signature.

DIRK FRANS WILHELMI. I 

